Various methods for forming patterns in asphalt surfaces and other substrates are known in the prior art. The Applicant is the owner of U.S. Pat. No. 5,215,402 which describes a method of forming a pattern in an asphalt surface using a removable template. The template is compressed into a pliable asphalt surface to imprint a predetermined pattern simulating, for example, the appearance of bricks, cobblestones, interlocking paving stones or the like. The template is then lifted clear of the asphalt surface and the asphalt is allowed to harden.
In one embodiment of the '402 invention a thin layer of a cementitious coating may be applied to the imprinted asphalt to enhance the brick and mortar or other desired visual effect. The decorative coating may be applied, for example, by applying concrete powder and a colorant in the form of a slurry which is spread throughout the asphalt surface and allowed to harden. This is a relatively time consuming and labour-intensive process. Various other acrylic, epoxy or latex-based protective coatings may similarly be applied to the imprinted surface after the impression step to seal the surface and enhance its visual appeal.
One drawback to the '402 method is that the decorative coating may wear off over time, particularly in high traffic areas. Further, as mentioned above, application of coatings in a liquid form is time consuming and poses technical difficulties. For example, if the coating is not spread to a consistent depth an unappealing visual effect may result. The need has therefore arisen for improved methods for coating asphalt surfaces by application of heat to pre-formed thermoplastic sheets.
It is known in the prior art to impress patterns in thermoplastic coatings on-site for functional or decorative purposes. For example, Prismo Universal Corporation has used and described a process for applying a relative thick layer (i.e. approximately 15 mm) of thermoplastic to an underlying substrate in a heated, pliable form. The thermoplastic is then manually stamped in the desired pattern by applicators wearing insulated, heat-protective clothing. The process is very labour-intensive and potentially dangerous. Since the stamping is performed manually, it is difficult to apply consistently render complicated patterns over large surface areas. Moreover, the stamping is intended to impress patterns in the thick thermoplastic layer rather than the underlying substrate.
The need has therefore arisen for improved methods and materials for applying a thermally settable coating to a patterned substrate, such as an imprinted asphalt surface.